We measured serum levels of estradiol (E2), sex hormone-binding globulin SHBG), progesterone, and dehydroepiandrosterone sulfate (DHEAS) in 61 postmenopausal women drawn from female residents in a community in Japan to evaluate the relationships between these hormone levels and potential breast cancer risk factors. The information on reproductive history, body size, alcohol use, and physical activity was obtained by means of a self-administered questionnaire. There was a significant trend in increasing E2 level with increasing height after taking account of age and body mass index (BMI) (p for trend = 0.04). BMI was inversely associated with SHBG level after controlling age (p for trend = 0.01). Decreasing progesterone with increasing BMI was observed after controlling age and history of hysterectomy (P = 0.05). Alcohol consumption was positively associated with E2 level and there was a strong linear trend after controlling for age, height, and BMI (p for trend = 0.001). Trend for increasing DHEAS with alcohol consumption was also statistically significant after controlling for age and history of hysterectomy (p for trend = 0.01). Reproductive factors as well as physical activity were not related to any of the hormone levels.